Reflects .c->.cc file renames across Geeqie.

Reflects .c->.cc file renames across Geeqie.

Commit auto-generated with:
$(for file in $(find src/ -iname '*.c' -type f); do export file=$(basename "$file"); echo "$file"; ruby -pi -e 'c_fi=ENV["file"]; c_re=Regexp.new("(?<!\\w)"+Regexp.escape(c_fi)+"(?=\\W)"); cc_file=c_fi.gsub(/\.c$/, ".cc"); $_.gsub!(c_re, cc_file)' $(find * -type f | egrep -v 'ChangeLog|\.png|\.icc') ; echo; done)